Photofragmentation in linked donor-acceptor molecules. Intramolecular single electron transfer induced cleavage of a 1,2-diamine
- Univ. of Rochester, NY (United States)
Two intramolecular donor-acceptor molecules which fragment by a single electron transfer initiated cation radical carbon-carbon bond cleavage have been synthesized and their photoreactivity studied. The intramolecular [open quotes]diads[close quotes] consist of a 1,2-diamine linked via an ester bond to either an anthraquinone or a 9,10-dicyanoanthracene electron-acceptor chromophore. As the covalent linkage between the donor and acceptor chromophores prevents solvent separation of the photogenerated radical ion pair, these systems provide a [open quotes]clock[close quotes] to examine directly competition between fragmentation and back electron transfer. The linked anthraquinone molecule fragments efficiently, with quantum yields approaching 80%, despite the inability of the photoproduced radical ions to separate. These high yields may be attributed to a slow, spin-forbidden back electron transfer and a rapid fragmentation. In contrast, the quantum yields for the dicyanoanthracene diad (reactive singlet) are markedly lower, less than 0.001 in benzene. The reactivity of comparable intermolecular donor-acceptor combinations is also reported. 54 refs., 3 figs., 2 tabs.
- DOE Contract Number:
- FG02-86ER13504
- OSTI ID:
- 5115348
- Journal Information:
- Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 115:18; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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250800 -- Energy Storage-- Chemical
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
AMINES
ANTHRACENE
ANTHRAQUINONES
AROMATICS
BINDING ENERGY
CHARGED PARTICLES
CHEMICAL REACTIONS
CONDENSED AROMATICS
DECOMPOSITION
ELECTRON TRANSFER
ELECTRONS
ELEMENTARY PARTICLES
ENERGY
ENERGY STORAGE
FERMIONS
HYDROCARBONS
IONS
LEPTONS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL ENERGY STORAGE
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
QUINONES
RADIATION EFFECTS
RADICALS
SOLVENTS
STORAGE
VALENCE